Aerial photograph image pickup method and aerial photograph image pickup apparatus

• US 9,007,461 B2
• Filed: 11/06/2012
• Issued: 04/14/2015
• Est. Priority Date: 11/24/2011
• Status: Active Grant

• Current Assignee: Kabushiki Kaisha Topcon
• Original Assignee: Kabushiki Kaisha Topcon
• Inventors: Ohtomo, Fumio, Otani, Hitoshi, Osaragi, Kazuki, Anai, Tetsuji
• Primary Examiner(s): Perungavoor, Sath V
• Assistant Examiner(s): AYNALEM, NATHNAEL B
• Application Number:
  US13/669,583
• Publication Number:
  US 20130135440A1
• Time in Patent Office: 889 Days
• Field of Search: 348/46, 348/144, 345/419, 382/154, 382/159
• US Class Current: 348/144
• CPC Class Codes: B64U 2101/30 for imaging, photography or videography
• CPC Class Codes: G01C 11/06 by comparison of two or more pictures of the same area
• CPC Class Codes: G03B 15/006 Apparatus mounted on flying objects
• CPC Class Codes: G03B 35/02 by sequential recording
• CPC Class Codes: G03B 37/02 with scanning movement of lens or cameras
• CPC Class Codes: G05D 1/0094 involving pointing a payload, e.g. camera, weapon, sensor, towards a fixed or moving target
• CPC Class Codes: G06T 2200/32 involving image mosaicing
• CPC Class Codes: G06T 2207/10016 Video; Image sequence
• CPC Class Codes: G06T 2207/10032 Satellite or aerial image; Remote sensing
• CPC Class Codes: G06T 2207/30181 Earth observation
• CPC Class Codes: G06T 7/33 using feature-based methods
• CPC Class Codes: G06T 7/593 from stereo images
• CPC Class Codes: G06V 20/13 Satellite images
• CPC Class Codes: H04N 13/20 Image signal generators
• CPC Class Codes: H04N 13/221 using the relative movement between cameras and objects

Abstract

The aerial photograph image pickup method comprises a first step of acquiring still images along an outward route and a return route respectively, a second step of preparing a stereo-image with regard to three images adjacent to each other in advancing direction, and of preparing another stereo-image by relative orientation on one more set of adjacent images and of preparing two sets of stereo-images, a third step of connecting two sets of stereo-images by using feature points extracted from a portion of an image common to the two sets of stereo-images, a step of connecting all stereo-images in the outward route direction and in the return route direction according to images acquired in the first step by repeating the second and third steps, and a step of selecting common tie points from the images adjacent to each other in the adjacent course and connecting the adjacent stereo-images in the course.

Claims

1. An aerial photograph image pickup method, comprising a first step of acquiring still images along an outward route and a return route respectively when a flying object flies in meandering manner up in the sky over an object range to be measured, a second step of preparing a stereo-image by relative orientation on one set of images adjacent to each other with regard to three images adjacent to each other in advancing direction, and of preparing another stereo-image by relative orientation on one more set of adjacent images and of preparing two sets of stereo-images, a third step of connecting two sets of stereo-images by using feature points extracted from a portion of an image common to two sets of stereo-images and the portion is an overlapped portion of said three images all together, a step of connecting all stereo-images in outward route direction and in return route direction according to images acquired in the first step by repeating the procedures of the second step and the third step, a step of selecting common tie points from the images adjacent to each other in the adjacent course and of connecting the adjacent stereo-images in the course, wherein prepares an unified stereo-image which covers the entire object range to be measured and is represented by common three-dimensional coordinate system.

2. The aerial photograph image pickup method according to claim 1, wherein an overlapping ratio overlapped in advancing direction is 70% to 90%, and a sidelapping ratio overlapped between the courses adjacent to each other is 40% to 60%.

3. The aerial photograph image pickup method according to claim 1, wherein feature points extracted from a still image are identified in an adjacent still image by the moving image tracking.

4. The aerial photograph image pickup method according to claim 1, wherein multi-image matching is performed on three images adjacent to each other along a course, and a stereo-image in the adjacent course is connected.

5. The aerial photograph image pickup method according to claim 1, wherein a still image photographing position is measured by a GPS device, model coordinates of a predetermined point on an object to be measured are determined based on coordinate value obtained by the measurement and based on said unified stereo-image, and the coordinate value obtained by the measurement is corrected by bundle adjustment based on the model coordinates and on said unified stereo-image.

6. The aerial photograph image pickup method according to claim 5, wherein said flying object has hovering function, the still image is acquired in hovering condition, a multiple of measurement values are acquired by said GPS device, and said coordinate value is an average of the measured values.

7. The aerial photograph image pickup method according to claim 5, wherein, for correction of said coordinate values, a photographing position is calculated by using said model coordinates, and a measured value within a predetermined threshold value is selected by comparing with the measured value of said GPS device at said photographing position, and calculation is carried out by using the measured value thus selected.

8. An aerial photograph image pickup apparatus, comprising a flying object, a GPS device provided on said flying object, an image pickup device for taking an image below said flying object, and a control device for controlling the flight of said flying object and for controlling image pickup of said image pickup device, wherein said control device controls said flying object to fly in meandering manner and controls said image pickup device to acquire still images in an outward course and in a return course and controls so that the images have a predetermined overlapping ratio in advancing direction, and so that the image has a predetermined sidelapping ratio between the courses adjacent to each other, and a still image pickup position is measured by said GPS device, and results of measurement are acquired by associating with the still images.

9. The aerial photograph image pickup apparatus according to claim 8, wherein said control device controls said flying object in hovering condition where the still images are acquired, and a multiple of results of measurement can be acquired on the image pickup position by said GPS device.

10. The aerial photograph image pickup apparatus according to claim 8 or 9, further comprising a data processing device, wherein said data processing device prepares stereo-images by sequentially performing relative orientation based on two images adjacent to each other in advancing direction, connects two sets of stereo-images by using feature points extracted from a portion of an image common to adjacent stereo-images which is an overlapped portion of three images constituting both of said stereo-images, selects tie points from an overlapped portion of the images adjacent to each other in an adjacent course, connects an adjacent stereo-image along the course based on a tie point, and prepares a unified stereo-image which covers the entire object range to be measured and is represented by a common three-dimensional coordinate system.